Thomas B. Woods

Computer Updates

The Newsletter For TS Computer Owners

Volume 3, Number | Winter 1986

THE NEW UPDATES

This issue marks a dramatic change in the newsletter. In our first two years,
subject matter was limited rather strictly to applications and enhancements for
the TS1000 version of ZX Pro/File. Now, the newsletter has broadened its scope.
Instead of detailing just one program, the new Computer Updates will provide
indepth information, new uses, program listings, hardware projects, computer
theory, and a sprinkling of philosophical bull about TS computers in general.

If possible, I will try to confine my wanderings to the area of the products I
sell. In this way, we both can benefit: I get a captive audience for my hyped-up
advertising campaigns, and you can make more intelligent (?) decisions about the
utility (???) of my products. Computer Updates will also function as an
"extended documentation" for the programs and peripherals I sell. As new ideas,
tips, discoveries, and uses come to being, you can read all about them in
Updates.

THE GREAT COMPUTER DEPRESSION
(What is This World Coming To Dept.)

A few weeks back, I took out a subscription to INFOWORLD, a weekly newspaper
featuring all the latest jive from the computer world. I figured that since I

was "in the business", it would behoove me to "keep my ear to the rail". The
paper would give me clues to what was happening in the other half of the
computer industry.

Let me tell you, every time I read that paper I get depressed! Its not that
INFOWORLD is a bad paper. It is the news itself that is so depressing. For
instance, did you know that Apple computer has filed suit against their founding
father, Steve Jobs. Apple alleges that Jobs has stolen trade secrets!

Another industry giant, Microsoft, has been accused of lacing their software
with a rather nasty message intended to scare the bejeezers out of anyone who
finds it. Apparently, some owners were trying to break into and modify the
program when a message came up Stating that they had no business breaking into
the program and that the machine was now destroying all data on the disk.
Microsoft really knows how to win friends and inspire confidence!

The more I learn about the rest of the computer world, the more I appreciate
ZX/TS world. Our dealings are with PEOPLE-- individual mom and pop type
businesses. The monsters who stab the knife in the backs of both their customers
and their founders ignore us. We're too small potatoes for them. And that's a
good thing.

But that's enough of the hard cruel world. Let's retreat to the Timex
tranquility. This issue has some very interesting projects and tips. Read on,
read on.

ANOTHER WAY TO SAVE
DATA IN PRO/FILE 2068

When you're running Pro/File 2068 and you
type "SAVE" from the main menu, program line
107 is executed which performs a normal
program save of the Basic program and all the
variables including DS, the large character
array which contains all your data. Many
people have asked if it would be possible,
instead, to save just the data and not the
program lines.

There are two advantages to saving in this

way. First, since you would not need to save
the lines of the program, cassette times

would be shortened. Actual time would vary
depending on how many records you have added.
Second, the data you save could be loaded

into other programs--either other versions of
Pro/File 2068 or completely different

software.

There have been quite a few people who made
some modifications to Pro/File 2068 only to
discover that when they tried to Load their
data into their new version, they also loaded
in the old unmodified program lines. The only
solution was to retype all the data back into
the enhanced Pro/File.

By changing the Save/Load procedures, you
won't need to re-enter all that data. Saving
time will be shorter, and you will be able to
isolate the data from the program. This means
you can write other Basic programs to operate
on your files in a way that Pro/File does not
(such as a search and replace procedure).

Computer Updates is published quarterly in
the winter, spring, summer and fall.
Subscription price is $12.95 per year. In
Canada and Mexico please add $3 postage. All
other foreign subscriptions please add $9
postage. Back issues are available as single
volume, 4 issue sets. Volume 1 is $9.95,
volume 2 is $9.95

Edited and published by:
Thomas B. Woods
P.O. Box 64, Jefferson, NH 03583
(603) 586-7734

copyright 1986, Thomas B. Woods

This technique converts the old program save
and load into a CODE save and load. Alter the
Basic lines 107 and 5510 so they read as
follows. You will need to do this in every

copy of Pro/File you use. After the lines are
changed, use the GO TO 1 command to get the
program running again. Now, with a spare
cassette in your recorder, type "SAVE" from
the main menu to save just your files.

After each Pro/File you have is saved in this
way, follow the instructions on page 99 of
the big book to make a back-up copy of your
original master. Once step 5 is completed,
alter lines 107 and 5510 just as you did
above. Then finish executing steps 6 through
9 of the back-up making procedure.

When you're finished, your new version will
operate in exactly the same way as before
except saving and loading times will be
reduced dramatically.

What do lines 107 and 5510 do? You can read
in the 2068 operator's manual that the SAVE

"name"CODE command, sends raw bytes of memory

out. to the tape recorder. You must tell the
machine the address of the first byte and the
number of bytes to send. Since DS is always
the first variable stored in memory, it is
easy to calculate its beginning address by
peeking the VARS system variable (23627 and
23628) and adding 6 to it. The Basic

variable, P, always tells how many bytes of
DS actually hold data. These two items
provide the necessary information so the
computer will know what and how much data is
to be saved.

Because each save varies in length, Pro/File
must update the variable P after a load so
its new value corresponds with the newly
loaded data. That's why the first part of
line 107 says,

LET DS( TO 5)=STRS P

Normally the first five characters of DS will

be the beginning of the *SEARCH IS COMPLETE

file. Line 107 temporarily overwrites this
with the number P. After the save is
finished, the same line restores DS(1 to 5)
to its old self.

Therefore, when line 5510 is called upon to
load data, the computer looks at the first 5
characters to get the corresponding value for
P. Before line finishes, it too, restores

these 5 characters to "*SEAR" so Pro/File
will function correctly.

Because data is saved as CODE (as opposed to
DATA DS), you must load the files into other
programs as CODE as well. On the surface, it
would seem that this is less than ideal
because most often you'd like to load it as

a string. Actually, this approach is more
versatile. In addition to being able to load
the data as CODE, you can also do just what
Pro/File does--create an array first, then

fill it up with the CODE. Essentially, all

you have to do is work up a program line that
looks something like this:

CLEAR: DIM DS(28000):LOAD " "CODE 6
+PEEK 23627+256*PEEK 23628

The CLEAR command insures that DS which is
created by the next statement will be the
first variable in memory and therefore at the
address calculated by peeking VARS.

In the dimension statement above, there is
nothing that prevents you from making D$ any
size you wish as long as you don't try to
make it smaller than the value for P. In

other words DS can be anything larger than P.
If P equals 2000, you could Dim DS to any
size greater than 2000. But don't try to make
it smaller. That's like trying to stuff 10
pounds of mud in a 5 pound sack. It just
won't work. Re-dimming D§ to a smaller size
is very useful at times, but means that
whatever data is stored in the array will be
lost. This trick lets you save off your

files, put them in a smaller array without
having to retype everything back in by hand.

HERE'S A CHEAP HOME BREW
TONE DECODER THAT WORKS GREAT!!

What's a tone decoder, you ask? Well, a tone
decoder is a vital piece of equipment which
must be hooked up in the Morse Code
Translator program for the Experimenter's
Universal In/Out Port. It is a circuit that
listens to audio dots and dashes from the
radio speaker and whenever the sound falls
within a narrow selected frequency, an output
goes high. Otherwise, the output is low. This
output signal is the one that is read by the
computer when the program converts the dots
and dashes into letters of the alphabet.

You can buy tone decoders from a variety of
sources, but they tend to be rather
expensive: $75 to $375 depending on quality
and features. An alternative to buying a
ready to go unit is to build your own decoder
using the diagram shown here. For $5-$10 you
can buy all the parts you need, and it will
perform superbly. In fact, this circuit works
far better than the commercial rig I
purchased for $100. Building it is a pleasant
evening's project. Considering its

simplicity, its just amazing how well it
works. Even in noisy, interference filled,
static conditions, this decoder pulls out

faint barely audible morse code. It literally
finds the needle in the haystack.

The parts can be purchased at Radio Shack or
your favorite electronics supply house. |

built my decoder on one of those
experimenter's solderless breadboards. This
allowed me to simply plug the components into
the board without soldering them. Usually,
soldering all connections is recommended by
the engineers. I won't argue with that, but

I really don't see how soldering could
improve the operation of this decoder other
than to make it more permanent. Perhaps the
best approach would be to build the decoder
up on the breadboard until you're happy with
the way it works. Then for the final version,
go back and solder the components together
permanently on a printed circuit board.

Here is a list of parts you will need:

1-Experimenter breadboard
1-XR2211 Tone Decoder Chip
1-LED (any type)

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LED +5vde
Capacitors This makes for a VERY selective tone decoder,

3-.1 uf capacitors
1-.47 uf electrolytic capacitor
1-.05 uf capacitor
1-.01 uf capacitor

Resistors (all 1/4 watt)

1-0 to 5 Kohm variable resistor
2-1 Kohm

1-100 Kohm resistor

1-16 Kohm

1-220 Kohm

As you build the tone decoder, try to keep
the component leads as short as possible. You
don't need use the values shown exactly. The
closest size you have will work just as well.
The exceptions to this rule are the .47 uf
electrolytic capacitor and the 100 Kohm
resistor. For these use only the values

shown. By increasing the value of the 220
Kohm resistor connected between pins 11 and
12 of the chip, you will narrow the "window"
of the tone frequencies which will send the
output high. As shown, the range is about 250
hz. Increase this resistor to a megohm and
the window will be only about 20 hz wide.

but one that is harder to tune your radio to.
The variable resistor connected between pin

12 and 4 (ground) lets you move the window up
or down in frequency.

To use this tone decoder with the Morse
Translator, apply 5 volts to the supply pin
(1) and connect pin 4 to ground. You can use
the computer's power supply if you wish, but
this will sometimes allow an objectionable
amount of noise to pass into the radio. A
better approach is to use a separate 5v
supply.

Use shielded cable to connect the speaker
output of the radio to the tone decoder
input. Hook the decoder output (pin 6) up to
bit zero of the input port following the
recommendations made in the Translator
documentation. Turn on your radio and tune
into some morse code. When you find a
transmission, adjust the tuning of both the
0 to 5 Kohm variable resistor, and also the
radio. When the tone is right, the decoder
locks into it, and the LED will blink in time
to the dits and dahs.

USE "DO" FILES TO CHANGE
PRINTER FORMAT IN ZX PRO/FILE

If you find that you frequently need to

change the print format (DEFP) in ZX Pro/File
for the TS1000, you can save a lot of
combersome keypresses by assigning a DO file
to do it for you. Since the print format is
stored in the three basic variables, Cl, C2,
and S, it is a fairly simple matter to set

their values in a program line rather than
input them from the keyboard.

Suppose you want to print out 3 lines
starting at line 6 of a file. Your DO file
program lines could look something like
this:

7000 LET Cl=8
7010 LET C2=6
7030 LET S=3

7040 GOTO 17

Remember, Cl always equals 2 more than the
number for the first line to Iprint. By

setting Cl to 8, line 6 will be the first to

be Iprinted. After you add these lines, set

up a DO file which jumps to the location of
your instructions. In this case it is line

7000, but it could be anywhere there is
space. When you enter the DO file as a Search
Command, the lines will be executed, setting
the print format as desired. Then, the last
line jumps you back to the Main Menu. NEAT!

Can anyone think of a way to make a DO file
set the print format to just one line and

then print lines in an order different from

the way they appear on the screen? This would
be like printing line 6, then 2, then 3, then 8.

UNCLASSIFIED

Sell that piece of gadgetry that failed the
smoke test; or that extra memory or printer.
Non-commercial ads just $5 for 5 lines!

FOR SALE: Two TS1000's, one TS2040 printer,
Byte-Back 64K RAM, EZ-Key 80 keyboard,
Q-Save filter and program, and miscellaneous
books, magazines, and programs. All for $275
or make an offer on pieces. Call (915) 944-
7970 after 6pm.

FOR SALE: Dot-Matrix Printer--C. Itoh Model
7500 Brand new, still in carton. Centronics
parallel type, print looks just like the
Prowriter. $250 Call Tom Woods,
(603)586-7734

BUILD A COMPUTERIZED ANEMOMETER
USING THE EXPERIMENTER'S I/O PORT

This project is the first in a series of
articles which will chronicle my ongoing
experiments in the development of a low-cost
completely computerized weather station
making use of TS computers, the
Experimenter's Universal Input/Output Port,
and a collection of common household items.

I think you will enjoy following my trials
and tribulations. After completing this first
part, it is apparent that there shall be some
very interesting computer concepts covered
here which will be applicable in many
different situations. If you decide that
you'd like to try building some of the
projects yourself, welcome aboard. Please
tell us about your ideas, experiments,
findings, failures and successes. Bear in
mind that above all else, I am a tinkerer;
not an engineer or electronics wizard. So
please, all you engineers and electronics
wizards out there, be forgiving when you see
my designs. Help out if you can by sharing
your thoughts.

An anemometer is a device which tells you how
fast the wind is blowing. Usually,

anemometers work by having some sort of arm
stuck up in the wind. The wind spins the arm
which is connected to the shaft of a

generator. The harder the wind blows, the
faster the arm spins. The generator will
produce higher voltage. By measuring the

volts, you can calculate the windspeed.

The anemometer I built operates on roughly
the same principal, except instead of
generating a voltage, the spinning arms of
the rotor slice through a light beam. The
computer is interfaced to the anemometer
through a light detector so what the computer
sees is a series of high and low pulses as

the arms break the light beam. As windspeed
increases, and the anemometer spins faster,
it is not a higher voltage which is produced
but a higher rate of pulses per unit of time.
In other words: a higher FREQUENCY. By
measuring the frequency, the computer

> §

Ew :

fs ° can calculate the windspeed.

a

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4

et ee es 7

a a
@ s: #F oe « 2 ®@ = ~— - 3s ° 7S wee
&o i 4 4 ni ( t 4@ 0 4 t t] 0 oe

Construction of the Mechanical Parts

Look at figure | to get an idea of how the
anemometer is constructed. A ping pong ball
which has been cut in half is used as the
wind collectors. When you cut the ping pong
balls, use a SHARP utility knife. After the
initial cut, trim the halves with scissors
until each is exactly the same size.

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Emitter

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TUBING

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Menving pLate

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Once you're finished with the ping pong
balls, set them aside and build the shaft
assembly. First, take a small mending plate
(or similar metal bar 3 inches long by 1/2
inch wide) and mark its center point. Cut a
piece of 1/4 inch copper tubing about an inch
and a half long. Ream any burrs that formed
on the inside of the tube as a result of the
cutting process. Make sure that the ends of

Bent Coat

«er wine

Infrared
\ Corrector.
a: Perf boaed

To computer

im, Tee ett rt af baa fn F “Raed
Ce ee 2 ToT 11 tt

the tube are straight and square. Run the
ends across a grind stone or file them if
necessary. A 16 penny common nail should
freely pass through the tube. Now use super
glue to stick one end of the tubing to the
mending plate. You should be able to look
inside the tube and see the center mark of
the mending plate in the exact center of the
tube. Go slow and get it right!

Use vice grips or pliers to squeeze the head
of the 16 penny nail into the end of a wooden
mast. This will allow the nail to stick up
straight. Wrap electricians tape tightly
around the nail and mast to secure.

Place the tube and mending plate rotor over
the nail. The rotor should spin with very
little drag. Mix up some epoxy and glue the
ping pong ball halves onto the ends of the
mending plate. Don't forget to face them in
the right direction, and take pains to insure
that the cups are spaced equally from the
center. While you're at it, gob a generous
amount of epoxy in the area where the tubing
connects to the mending plate. Spread the
epoxy right around the tube and over the top
face of the mending plate. A lot of stress
will build up here in a high wind.

As in all rotating objects it is important to
try to keep the rotor properly balanced. That
is why you should be careful in your
positioning of the tubing and the ping pong
balls. Before you clean up the epoxy, try
spinning the rotor gently. If you see it

wobble and shimmy, place a bit more epoxy on
the mending plate to bring it into balance.

Electronics Construction

While you're waiting for the epoxy to harden,
begin work on the electronic portions of the
anemometer. As mentioned previously, a light
emitter and detector circuit must be located
at the rotor. It must be positioned so that
the light path between the two will be broken
by the mending plate as it spins. Use the
schematic diagram and the drawing shown in
figure 2 as a guide in fabricating the

circuit on a small piece of perfboard. Use
about 6 inches of lead wire soldered to both
the infrared emitter and detector.

After all connections are soldered, cover the
board completely with electrician's tape to
protect it from the weather. Then tape it to
the wooden mast as shown in figure 1.

Cut up a coat hanger and form it in a shape
similar to that shown in figure 1. Use a wood
screw to fasten it to the end of the mast.
You want to bend the coat hanger so that it
will hold the emitter and detector about an
inch apart, and at the same time allow the
cups of the rotor to spin freely. Use more
electrician's tape to secure the emitter and
detector as well as the lead wires to the
coat hanger wire. Be sure the emitter is
lined up so its light can be seen by the
detector.

If you wired the circuit up properly, you
should have three leads coming down off the
mast. They go into your computer room. The
+5vdc and ground lines can connect directly
to your computer. I did this by soldering two
wires to the power pins on the underside of
the I/O port edge connector. If you turn the
port upside down, the +5 volt line is on the
extreme right side. The ground is the fat
trace immediately to the left of the key
slot. The third line coming from the mast is
the data line which must be fed to the input
of an LM339 quad comparator chip which is
shown in figure 3.

The comparator chip functions as a "level
detector". It compares the voltage coming
from the light detector (at pin 5) with a
reference voltage (at pin 4) which can be
adjusted by turning the 100 Kohm variable
resistor shown in the schematic. Whenever the
voltage from the light detector is greater
than the reference voltage, a high signal is
output to pin 2. When the voltage from the
detector is less than the reference, pin 2
goes low.

The comparator is essential for cleaning up
spikes and glitches coming in from the light
detector. The adjustable reference voltage
takes into account different voltage drops

which occur when you set the anemometer up at

various distances. The comparator's output is
a nice sharp 0 to 5 volts--just perfect for
sending into the computer via the input
port.

Build the comparator circuit on a piece of
perfboard or a solderless breadboard. Supply
it with 5 volts from the computer. Every data
sheet on the LM339 I've read says that you
must ground all pins of the chip which are
not used. While this may very well be a good
practice, I have found that doing this has no
effect on the circuit. So for convenience and circuit and the emitter/detector circuit.
simplification, don't bother grounding the Also, tie the data line from the anemometer
pins. Besides, we may want to use the 3

to its proper location in the LM339 circuit.
unused comparators in the LM339 for something Use wire nuts or just twist the wires
else later.

Plug the port into the back of the computer
and turn it on. For testing, you don't need

the computer for anything other than its
power supply.

Temporarily connect the power lines up to
their respective leads of the comparator

Detector Emivtten
Testing the Anemometer

Before you permanently install the (+)
anemometer, you will want to test it inside.

With my rig, I used a four foot long mast.

It was held in a vice on the floor. A fan

was directed at the cups on the mending (YJ /(+)
plate. The fan gave it a nice slow spin of

about | revolution per second. In your tests,

you will find that it is much easier to see

what's going on if you keep the anemometer To
from spinning too fast. For now, the slower
it spins, the better.

. <3
Hook up wires to the +5 volt and ground lines Ground
of the port board as previously described.

Te M339
25: o L

Computer

+ 5vde

Figure 2,

1 Ka Infrared

Detector (#276- 142)

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together. Turn on the fan so it spins the
anemometer. Use a volt meter to measure the
voltage between pin 5 of the comparator and
the ground.

This is the data line coming in from the
light detector. The actual voltage measured
depends on many factors. It will be different
for each set up. What you should see is a
definite swing of at least 1 volt as the
anemometer spins. In my test, I measured a
high voltage of just under 3 volts and a low
voltage of just over | volt.

Now measure the reference voltage at pin 4 of
the LM339. By turning the variable resistor

in the circuit, you should be able to adjust
this voltage through the range of 0 to 5

volts. Set the voltage at the pin to the

highest possible setting (5 volts).

If you measure the output of the LM339 (pin
2), you will see that it is now very close to
0 volts. This is because the input from the
light detecter is less than the reference
voltage (5 volts at pin 4). Watch the voltage
at pin 2 while you slowly turn the variable
resister to lower the reference voltage. At
some point, you will begin to see the pin 2's
output voltage swing between 0 and 5 volts as
the anemometer spins. It is at this point
where comparator is allowing the data from
the light detector to pass through and you
know you connected the circuit properly.

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One last thing you should do before you
install the anemometer outside is to lift the
rotor off the nail and paint the bottom side
of the mending plate black. I discovered that
if the mending plate was not blackened,
bright sun can reflect off the rotor arm and
trip the infrared detector. This was
particularly noticable (and also a real
headache til I discovered what was happening)
on a bright day with fresh snow cover.

Outdoor Installation

Windspeed, of course, varies tremendously
from place to place. It can show significant
differences between ground level and 10 feet
up in the air. Bushes, trees, buildings, and
hills all cause variations which are quite
unpredictable. You want to locate the "most
average" spot you can for your anemometer.
You also want to keep it as close to your
computer as possible.

Keep the anemometer well away from (or above)

trees, buildings, or other physical
obstructions which can cause sheltering or
turbulence. Many people mount their
anemometers on rooftops. If this is not
possible, construct as tall a mast as you can
(like a 16 foot long piece of 2x4) and place
it as best you can "out in the open".

Interfacing to the Computer

With the computer turned OFF, plug your
printer interface and the Universal In/Out
Board into the back of the computer. You may
need to fabricate some sort of extender off
the back of the machine to accomplish this.
If you have not done so already, tap into the
+5v and ground lines as described previously
and use them to power the LM339/light
detector circuits. Hitch the output of the
LM339 (pin 2) to bit 0 of the input port.
Your computer is now ready to measure the
wind.

Now the Software

Enter this listing into your TS1000 and save
it. (2068 OWNERS NOTE: a 2068 version of this
program appears at the end of this article).

10 LET AS=CHRS 1+CHRS O+CHRE 0
+CHRS® 116+CHRS 62+CHRS 60+CHRS 5S
O+CHRS S2+CHRS 64+CHRS 219+CHRS
223+CHRS 95S+CHRE SS+CHRS S2+CHRS

64+CHRS 254+CHRS 0+CHRS 200+CHR
@ 219+CHRS 223+CHRS 187+CHRS 40+
CHRS 245+CHRS 3+CHRS 24+CHRE 241

20 LET WIND=3+PEEK 146400+256%P
EEK 16401

30 SLOW

40 PRINT “RELATIVE VELOCITY:";
AT S,03;"TRANSITIONS PER SECOND:"

S50 PRINT AT 3,03;"0....1....20.
codec eeFeccedeve sO”

60 LET Y=0

70 LET P=90

80 PRINT AT 16,0;"PRESS -P- FO
R LPRINT -Q- FO
R SCREEN ONLY“

LET X=USR WIND

UNPLOT Y,38

PLOT X,38

LET Y=xX

PRINT AT 5,233X;3" .

IF INKEY$S="P" THEN LET P=10

IF INKEY$="Q"
GOTO P

REM HARD COPY
LPRINT CHRS 155;"RP";"RELAT
IVE VELOCITY"
1020 LPRINT “
ee ee ee — ie
1030 DIM S%#¢32)

THEN LET P=90

Ove ie dees 2 ese os

1040 LET T=0
1050 LET Pe oie betel deseo 1B ote eck e858

1060 LET 2=1

1070 LPRINT CHRS 155;"RTO2"

1075 LET X=xX+1

1080 IF X<=2 THEN LET D$=S$¢ TO
X-1)+P$¢(X TO Z)

1090 IF X>2 THEN LET Ds=S8¢ TO Z
~1)+P$¢(Z TO X)

1100 IF T=0 THEN LPRINT “-";3Ds
IF T<>0 THEN LPRINT "— "53D
LET T=T+t1

IF T=10 THEN LET T=0

LET 2=X

LET P=1075

GOTO 90

When you RUN the Basic (Don't use GOTO here),

the computer plots the current relative wind
speed on the screen in the form of a "sliding
pixel". The program will also Lprint a graph
of the data if you press "P". Because the
Basic spends most of its time reading the
anemometer, it checks the keyboard only once
per second or so. If you find that pressing

"P" has no effect, just hold your finger down
a little longer.

You will need to alter the Lprint routine
beginning at line 1000 to match your
individual printer. The listing works with

the Prowriter and the Memotech centronics
interface. In line 1010, the command, LPRINT
CHRS 155;"RP" puts the Prowriter into
proportional spacing mode. The LPRINT CHRS$
155;"RT02" in line 1070 changes the line feed
pitch to just 2 dots per line feed. The

result is a fairly nice graphics printout

just by printing a series of periods (.)! A
sample printout of a fairly calm day here in
Jefferson is shown.

To explain how this program works, let's
review what the anemometer is capable of
doing so we can see what tasks the software
has to perform. Esentially, we have a rather
fancy switch mounted at the top of a long
stick. The rotor and wind cups cause the
switch to open and close as the wind blows.
The faster the wind blows, the more
frequently the switch opens and closes.

To determine the wind speed, therefore, we
must find out just how often the switch opens
and closes in a fixed unit of time. One way
to measure time with the TS1000 is to

capitalize on the hardware generated
interrupt signals which occur at the rate of
60 pulses per second.

When the computer is in the SLOW mode, each
interrupt causes the system to generate the

TV display. In addition, the system variable
FRAMES (address 4034 and 4035 hex) is used to
count each interrupt. The value stored in
FRAMES decrements each time an interrupt
Signal is generated by the computer.

A short machine code routine counts the
number of times our light detector switch
opens and closes during the period of 60
interrupts (approximately 1 second). The
program samples the input from the light
detector and compares it with the previous
sample. If the two are different, meaning the
rotor arm has either left or entered the

light path, a counter increments. Each
transition from low to high and high to low
adds one to the count. This process continues
until 60 interrupts have occured. Then the
machine code returns to Basic.

The rotor causes 4 transitions in the light
detector per revolution. In one complete
turn, one end of the rotor breaks the light
path causing a change from high to low. As
the arm continues out of the path, the second
transition from low to high occurs. The
revolution completes when the other end of
the rotor causes two more transitions from
high to low and low to high.

The actual machine code that does the
counting appears below. Although it is
written for use on the TS1000 type computer,
you could very easily run it on the TS2068.
Only the address of FRAMES (4034 hex) is
different. The necessary changes are
incorporated in the 2068 listing.

Bissaae BEGIN LO BC. 8806
7S HAL

ny Heo (0 CO ce
ie)
vu
m

ENN CORI Ca

Pee ye

To start, the code loads BC with the initial
count of zero. Then the HALT instruction
causes the computer to wait until the first
interrupt. The hex number 3C (or 60 in
decimal!) is placed in the FRAMES system
variable (address 4034). This represents the
time the machine code will spend counting
transitions which the computer now starts to
do. The IN A,(DF) instruction reads the
initial state of the anemometer's light
detector. It will either be high or low. The
value found is stored in E. After each
sample, FRAMES is checked for a zero value by
the code starting at the label CNT_.

The interrupts cause FRAMES to decrement
"automatically" so after each, FRAMES will
equal FRAMES-1. Eventually, it will reach
zero and the computer will return to basic.

As long as FRAMES does not equal zero, the
code labeled SMPL will execute. Here, another
IN A,(DF) instruction samples the port. The
value found is next compared with the value

in the E register. As long as the two are the
same, it means no change has occured, and the
code jumps back to see if FRAMES has reached
zero yet. When the values in E and A are
different, we have a transition. Therefore,

the code increments BC and loops back to the
label STOR which puts the new value in E
before repeating the whole sequence.

Because BC is used to count transitions, the
machine code returns with X=BC or put
differently, X equals the total number of
transitions.

The Basic portion of the program performs the
tasks of storing the machine code and
executing it. Then it displays the

information generated by the machine code
graphically. I am sure you will want to
experiment with different display formats.
What is presented is intended to be a

starting point--not the ending point.

The only lines you should NOT tamper with
(unless you can program in machine language)
are the first three: lines 10, 20, and 30.

Line 10 contains the machine code. It is

stored in the form of a string rather than

the customary REM line because the second
machine code instruction, HALT, cannot be
placed in a REM without crashing the :
computer. Thus, we keep the code out of a REM
line!

Line 20 determines the starting address of

the code so we know where to jump to execute
it. Since AS is the first variable

initialized, its location can be found very
easily. All you have to do is add three to

the value stored in VARS (address 16400 and
16401 decimal). This is what is done by line
20.

Line 30 is essential to the execution of the
machine code. Whenever you run code which
uses the HALT instruction, you MUST put the
computer in SLOW first. If the computer
executes such code in FAST mode, you crash
because interrupts are disabled in FAST.
Without interrupts, the HALT instruction will
cause the computer to wait forever.

Aside from that, you are completely free to
add whatever additional Basic you want. Just
be sure you write your program so you can use
RUN to start it. In this way, the machine
code will always be in the right place and

you will always be in SLOW mode. Any time you
want the rotation rate of the anemometer just
execute the command LET X=USR WIND. This
makes X equal to the number of times the
rotor sliced through the light beam in one
second. From that, you can print it, plot it,
store it, or whatever.

Converting "Relative Velocity" into
MILES PER HOUR

If you have been wondering why I have not
programmed this into the Basic already, well,
errrr, it's because I haven't figured out how
to do it yet. Surely, you helpful readers can
come to my rescue. I have heard of others who
devised an ingenious plan of sticking the
anemometer out of their car window and
driving down the road at several known
speeds. This would work in our case too, but
hooking up the computer, a monitor, etc.
would be quite an undertaking.

Another method which is less exact, but more
appealing (to me at least) is to call several
local airports, weather stations, etc. and

take an average which could be factored in to
the program. By calling several such places,
and doing it many times, you should be able
to reach a fairly high degree of accuracy.

Perhaps easier still is the "estimating by
phenomena" approach which I copped out of the
book, WIND AND WINDSPINNERS by Michael A.

ae ae

Hackleman. Using this method, you translate
trasitions per second into miles per hour by
relating other natural phenomena. Refer to
the table below which was taken from
Hackleman's book: nat

MPH Phenomena
0 Smoke rises vertically

1-3 Smoke drifts in direction of wind

4-7 Wind felt in face, leaves rustle

8-12 Leaves, small twigs in constant
motion

12-18 Dust, loose paper rises, small
branches move

19-24 Small trees begin to sway. Wavelets
form on pools

25-31 Large branches move. Phone wires
whistle

32-38 Whole trees move. Walking difficult

39-46 Twigs and branches break off trees

47-54 Flower pots and house tiles are
removed

Conclusion

I hope this article perks your interest this
unusual use for your computer. In future
issues, I will incorporate other weather
monitoring devices into the foundation layed
here. Wind direction is certainly high on the
list, as is temperature, barometric pressure,
and humidity. Other data which would be fun
to collect are sun light intensity, soil
temperature, and precipitation (both quantity
and acidity). A seismometer (earth tremors)
would be interesting to experiment with as
well. The exciting thing is that all these
things can be done with TS computers and a
little Rube Goldberg type inventiveness, and
all of it requires the use of just one
computer and one input port. Have fun!

TS2068 Listing

iQ LET AS=CHRS 14+CHRS O+CHRS 2
+CHRS L1S+CHRS$ S2+CHRS 195+CHRS
S@+CHRS BE ceca S2+CHRS$ 219+CHR
$ S2SS+CHR$ SS+CHRS SS+CHRE$ 120+c
HR$ SS+CHRS S54+CHRS$ B+CHR$ SaG+
CHRS S1S+CHR$ S23+CHRS$ LE7+CHRS
4Q+CHRS S454+CHRS$ BS+CHRS 244CHRE

241i
28 LET WIND=S+PEEK 23627+256<4P
FER 23625

a p"O.scclese see:
"68 LET vie: LET p=90
20 PRINT AT 16,0; "PRESS -P- Fo
LPRINT -G- FO
SCREEN ONLY”

Rakea)

SQ LET XsUSR WIND ot Ee Pete
168 PRINT AT ¢2.%¥- ” ; AT W2:%¢2
Se EW SxS éRINT ar’ E,25;%;7

148 IF INKEY$="P" THEN LET F=i8

15@ IF INKEY$="Q" THEN LET P=38
1689 Go To P
19@@ REM HARDCOPY
1918 LPRINT CHRS$ 27; "P"; “RELATIV
E VELOCITY”
1928 LPRINT ©

oie eee ie

De asc a

= pretest ae eae ssses eee Be eee Be eases

ee: LET =i”

i@7@ LPRINT CHRS 27; "Tee"

1975 LET X=x4i

186@ IF X<=Z THEN LET D$=5%' TO
K-Li+Psix TO 2)

igsea IF _x = THEM LET O$=5$( TO Z

-1Li4+F$ 12 To

1168 IF T=8 THEN LPRINT °“-";,0%
11108 IF T<+:@ THEN LPRINT "” " DS
Pee LET T=T+1: IF T=18 THEN LET
T=

oT 30 LET 2Z=xX: LET P=18a75: Go Ta
ou

BUGS, NEWS, AND MISCELLANEA

Pro/File 2068 owners take note! A few

fustrated folks who added the new Machine
Code Sort capability from the BREAKTHROUGH
newsletter experienced crashing problems
whenever they tried to alphabetize files by

one particular line, but ordering by any

other line worked fine. This is a bug in the
machine code--not a typing error.

Robert C. Fischer, 221 Scoggins St.,
Summerville, GA 30747 was able to pinpoint
the exact effect. He wrote, "If you compare

a line of data in different files, and the

data matches EXACTLY, but if in one case the
data is the last line of a file while in the
other it is not, the program crashes. The
routine can't handle a comparison of * and
code | which signify the end of file and end

of line markers respectively."

What does this mean? Well, basically, it
means that you should avoid sorting any file
on the basis of the last line. A more prudent
approach would be to use the first few lines
of each file to store "sort codes" and use

the remainder of the file to store other data
which would not be sorted. Unfortunately, it
would be a major task to fix this bug. It is
far easier to arrange your data in such a way
that the bug will never rear its ugly head.

To all of you who ran into problems with this
and thought you were losing your sanity,
please accept my apologies for not spotting

- 13-

this problem. We can ail thank Bob Fischer

- for accurately describing it. Incidently, Bob

publishes a newsletter called "Extensions"
which features adaptations and enhancements
to the Pro/File 2068 program. He has come up
with some pretty neat things which you should
check out. Extensions is a bargain at just

$6. Write to Bob for your copy soon.

Another rather curious bug in the TS2068 32K
Non-Volatile Ram board has been fixed. A very
few of the first boards produced would end up
with a dead battery after the board had been
left in the computer for a few hours. We
checked chips, batteries, diodes, virtually
everything we could think of and still

couldn't find the leak. Imagine our surprise
when we found it was the battery prong
touching the inside of the TS2068 case (which
has a grounded conductive coating on it to
reduce RF noise). It was a dead short!
Anyway, a small piece of electricians tape
over the battery prong makes the board last
practically forever. We estimate that in
"storage mode", that is, when it is removed
from the computer and is powered solely by
the on-board lithium cell, the memory will
retain its contents for about 145 years!

Finally, here's a hopeful tidbit. Tom Bent,

the creator of the 32K Non-volatile RAM, is
hard at work figuring a way to use this
memory on the TS1000! He reports that a
TS1000 rear connector for the memory board is
close to being operational.

ZX81 EXTENDED BASIC NOTES

Robert Shade from Philadelphia was studying
the DEMO program which comes with Extended
Basic and asked what function all the OUT
commands perform. According to Frits Beniest,
author of the program, and programmer
extraordinaire, these commands were included
to generate sound from the ZON-X sound
generator. This peripheral is available in
Europe, but to my knowledge, is not
distributed here in North America.

If we had this device plugged in to the
TS1000, we would have an autitory melee of
bangs, roars, bells, and whistles
accompanying the dazzling visual display. As
it is, you could delete every OUT command,
the only effect being a slightly faster
program run. It is hard to imagine the demo
going any faster though, even if it were
written in machine code!

i e 5 : #2

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